DISTRIBUTION OF DETRITAL SEDIMENT CAPTURED IN MCKAY BAY MEMBER KNOLL REEF, UPPER PENINSULA, MICHIGAN

The reef systems of the Michigan Basin have been investigated since the 1930’s. However, little research has been conducted on its knoll reefs that exist in outcrop. Knoll reefs are carbonate mounds that form in shallow waters, which hamper the reef's ability to grow vertically, forcing the reef to grow horizontally instead. The knoll reefs in this study are stratigraphically located in the McKay Bay Member, in the Bush Bay Formation, of the early- Silurian Engadine Group. The knoll reefs are found in the Hiawatha National Forest at the eastern end of Michigan’s Upper Peninsula.

This project is a preliminary investigation into the origin and distribution of detrital sediment captured in of the largest knoll reef in the study area. Over 100 hand samples and cores were collected at 1-meter intervals across the reef. The samples were collected in a transected grid pattern every 22.5 degrees and are being analyzed through petrographic analysis. Detrital sediment for each thin section is point counted to create rose diagrams. This will show the direction of detrital sediment influx for the reef.